The WinSystems WS16C48 device provides 48 lines of digital I/O accessed
via six 8-bit ports. Since eight input lines are acquired on a single
port input read, the WS16C48 GPIO driver may improve multiple input
reads by utilizing a get_multiple callback. This patch implements the
ws16c48_gpio_get_multiple function which serves as the respective
get_multiple callback.
Signed-off-by: William Breathitt Gray <vilhelm.g...@gmail.com>
---
drivers/gpio/gpio-ws16c48.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/drivers/gpio/gpio-ws16c48.c b/drivers/gpio/gpio-ws16c48.c
index 746648244bf3..6d911f8e92c1 100644
--- a/drivers/gpio/gpio-ws16c48.c
+++ b/drivers/gpio/gpio-ws16c48.c
@@ -129,6 +129,44 @@ static int ws16c48_gpio_get(struct gpio_chip *chip,
unsigned offset)
return !!(port_state & mask);
}
+static int ws16c48_gpio_get_multiple(struct gpio_chip *chip,
+ unsigned long *mask, unsigned long *bits)
+{
+ struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
+ unsigned int i;
+ const unsigned int gpio_reg_size = 8;
+ unsigned int bit_word_offset;
+ unsigned int bits_mask;
+ const unsigned long reg_mask = GENMASK(gpio_reg_size, 0);
+ unsigned int in_port;
+ unsigned long port_state;
+
+ /* clear bits array to a clean slate */
+ for (i = 0; i < chip->ngpio; i += BITS_PER_LONG)
+ bits[i / BITS_PER_LONG] = 0;
+
+ /* get bits are evaluated a gpio register size at a time */
+ for (i = 0; i < chip->ngpio; i += gpio_reg_size) {
+ bit_word_offset = i % BITS_PER_LONG;
+ bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset);
+ if (!bits_mask) {
+ /* no get bits in this register so skip to next one */
+ continue;
+ }
+
+ /* compute input port offset */
+ in_port = i / gpio_reg_size;
+
+ /* get input bits */
+ port_state = inb(ws16c48gpio->base + in_port);
+
+ /* store acquired bits */
+ bits[BIT_WORD(i)] |= port_state << bit_word_offset;
+ }
+
+ return 0;
+}
+
static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int
value)
{
struct ws16c48_gpio *const ws16c48gpio = gpiochip_get_data(chip);
@@ -383,6 +421,7 @@ static int ws16c48_probe(struct device *dev, unsigned int
id)
ws16c48gpio->chip.direction_input = ws16c48_gpio_direction_input;
ws16c48gpio->chip.direction_output = ws16c48_gpio_direction_output;
ws16c48gpio->chip.get = ws16c48_gpio_get;
+ ws16c48gpio->chip.get_multiple = ws16c48_gpio_get_multiple;
ws16c48gpio->chip.set = ws16c48_gpio_set;
ws16c48gpio->chip.set_multiple = ws16c48_gpio_set_multiple;
ws16c48gpio->base = base[id];
--
2.16.2
